Lighten Up Blog

Study Shows How Increased Reflectivity Can Save Lives

Posted by gcca on October 8, 2014

Researchers at the Georgia Institute of Technology recently published a report, in which they took a look at past heat waves in Phoenix, AZ, Philadelphia, PA and Atlanta, GA.

This study shows that by adding white roofs, reflective pavement and trees, cities can counteract temperature increases in urban areas and save lives. From an article byClimateWire …

[T]he researchers modeled how the three cities would respond to a minimum green space ratio on land parcels, setting a floor for areas covered with grass, gardens or trees. Vegetation tends to have a cooling effect by circulating moisture in the air that draws away heat during evaporation. Tree canopies also provide cooling shade.

The team also modeled how Phoenix, Philadelphia and Atlanta would behave with more reflective streets, sidewalks, parking lots and rooftops. Higher reflectivity, or albedo, means the area absorbs less sunlight, thereby lowering the temperature.

Stone and his collaborators then overlaid a health impact model. They found that combinations of increased vegetation and albedo could cut into projected increases in heat deaths, reducing them between 40 and 99 percent. “On average, we reduced the rate of increase by about 60 percent,” Stone said.

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Groups like the Global Cool Cities Alliance are now trying to get cities to adopt these adaptation strategies, pitching them as a way to protect public health. However, it’s slow going, given that cities around the country address heat vulnerability differently, if at all.